1. Field of the Invention
The present invention relates generally to measuring a parameter of a multiphase flow in a pipe. More particularly, the present invention relates to buffer chamber assemblies which are coupled to a pipe proximate a pipe tap. The buffer chamber assembly serves as a means to sense parameters of the fluid in the pipe, to sample the fluid in the pipe, and to introduce fluid to the flow in the pipe, while resisting the clogging of the pipe tap.
2. Description of the Prior Art
Pipe taps, particularly pipe taps that are coupled to parameter measuring devices, such as pressure measuring devices, are typically ineffective when used on pipes carrying fluids which tend to clog. The clogging that attends the flow of some fluids that are typically transported in pipes rather quickly partially or fully occludes the tap opening, thereby affecting the accuracy of the parameter measurement. The tap in the pipe may be remotely located and clearing of a clogged condition may pose considerable problems, not the least of which is the potential need to shut down flow in the pipe during the cleaning operation.
U.S. Pat. No. 5,312,137 by Nee discloses a safety shield for capturing corrosive fluids escaping from a joint in a piping system. The safety shield includes an aperture to encircle a pipe and an outlet. Devices may be included which measure the conditions within the shield.
U.S. Pat. No. 4,040,289 by Clark discloses a method and an arrangement for air testing of sewer lateral connections. The tester is pressurized with air over the lateral connection location and the air pressure monitored. If the tester holds pressure, the connection is deemed leakage proof.
U.S. Pat. No. 5,330,720 by Sorbo discloses a system for detecting gaseous emissions from a mechanical coupling. The housing comprises a semi-permeable material which allows the gases to escape while preventing foreign matter from entering the housing.
U.S. Pat. No. 5,022,271 by Hannon, Jr., discloses a pressure sensing device for pipes carrying corrosive or abrasive fluids. The device measures pressure in the pipe by the movement of a thin metal wall incorporated into the pipe. The thin metal wall includes pleats or folds which allows the wall to move inwardly or outwardly in response to changes in pressure.
U.S. Pat. No. 4,840,068 by Mayhew, Jr. discloses a pressure sensor assembly which measures pressure by the movement of a diaphragm included in a pipe wall. A chamber upon which the pressure sensor is mounted contains a pressure sensing fluid kept separate from fluid in the pipe by the flexible diaphragm. The flexible diaphragm flexes outward or inward causing the sensing fluid to pressurize of depressurize. There is no mixing of the pipe fluid and the sensing fluid.
U.S. Pat. No. 5,347,868 by Shigesada discloses a pressure gauge designed for use in measuring the pressure of thixotropic (colloidal) liquids. The object of the invention is to prevent aggregation stagnation of the fluid by controlling the stagnation of a magnetic coating liquid in the vicinity of a pressure sensor. Aggregation of fluid near the pressure gauge is subsequently reduced.
There is a need for a pipe tap which resists clogging and minimizes the corrosive effect on parameter sensors from corrosive fluids being transported in the pipe. The pipe tap should be inexpensive to manufacture and highly effective. Such a buffer chamber assembly must reduce clogging near a parameter sensor, thereby making more accurate readings as to the various parameters of the fluid. Additionally, such a buffer chamber assembly should be simple to use, especially when readings must be taken in the field under potentially hostile environmental conditions. Such a buffer chamber assembly should also utilize existing tools for mounting on pipes rather than requiring specialized equipment.